The present invention generally relates to impact energy attenuation, and particularly to padding and cushioning systems intended to reduce trauma resulting from impacts to parts of the body, such as the head. Moreover, the present invention relates the general personal protection field, in general, which includes helmets, pads, armor, sports gear, clothing, worker safety equipment, packaging, vehicle interiors, barriers and pads for threat objects, and the like.
The present invention relates to a new and novel way to attenuate impact energy using loose particles contained in resilient structures while being arranged and customized to optimize such attenuation of energy.
For ease of discussion and illustration, the present invention will be illustrated and discussed in detail in connection with the field of personal protection, namely, helmets. This is just one example of the many applications of the present invention. It should be understood that this in no way intended to limit the scope of the present invention.
In the field of personal protection, protective gear for professional and recreational athletes, sport enthusiasts, military personnel and construction workers are well known in the art. There are many approaches to reducing impact energies transferred to the user during an impact. As can be well understood, protection of the head is of high concern due to the risk of head trauma and other serious injuries. Therefore, protection of the head is of critical importance.
In the prior art, helmets are well known to protect a users head from skull fractures and other such trauma. This was accomplished primarily by some type of rigid outer shell. Over time, padding was added to replace webbing based suspension systems. Although padding has improved, these prior art systems still have significant problems and suffer from many disadvantages. One typical shortcoming of prior art helmet protection systems is inadequate protection over a range of impact energies typically encountered in activities they were intended for. Another typical shortcoming of the prior art is their inability to significantly reduce rotational (off axis) impact energies. Another typical shortcoming of the prior art is their inability to consistently fit a large range of users head shapes and sizes. Another typical shortcoming of the prior art is using impact energy attenuation systems designed for adult helmet systems in children's and youth helmets.
There are many types of helmets provided in the prior art in an attempt to address the foregoing concerns and shortcomings in prior art helmet design. Contact sports such as American football, hockey and lacrosse have developed and refined helmet types suited to the play of those sports while decreasing head injuries. Similarly, climbing helmets, snow sports helmets motor sports helmets and bike helmets have evolved and are widely worn by recreational and professional users. A majority of these helmets employ a rigid or semi-rigid shell. It is understood in the art, that a hard shell protects the skull from fracture and distributes the impact energy over a larger area. Most bike helmets utilize expanded polystyrene material for their construction. This approach to the shell/padding allows for a light weight, affordable product.
In addition, most helmets have fit systems allowing the user to adjust the size of the helmet to better fit their head. Fit is known to have a large impact on the efficacy of any helmet system by maintaining coverage during a potential impact situation. Rigid shell systems are challenged to provide an optimal fit given the range of human head shapes and sizes. Many prior art helmets use pads of the same thickness throughout and typically result in either loose areas, tight areas or both when fitted to a users head. Helmets that use foam pad systems, for example, may have areas that fit tightly and since the foam in those areas is overly compressed, impact mitigation is compromised. Conversely, loose areas do not benefit from additional protection afforded by that dimension. Expanded polystyrene (EPS) bike helmets, for example, are rigid throughout where the shell and pad system are one and the same. As a result, they offer little or no ability to establish an optimal fit.
Still other systems include air bladders, which can be filled to occupy voids between the users head and the shell. Still other systems use variable length head bands that can be adjusted to fit the circumference of the users head. Variable length head bands leave potentially large voids between the band and the shell. User applied low durometer foam pads are also well know to adjust fit, but do little to attenuate impact energy.
In addition, most helmets employ a retention system to ensure the helmet stays properly aligned on the users head. These are typically webbing straps, sometimes including a cup or other interface for the users chin.
As indicated above, all of the forgoing issues also relate to any type of protective equipment and devices and not limited to those that are intended to protect the body. Therefore, the same issues are of concern outside of the field of the personal body protection, of which the present invention is also related and has applicability.
Referring specifically now to padding, there are many known systems, a number of which are discussed below. One common approach for padding in the prior art is the use of foam materials. Foam materials are based on a manufacturing process that creates an open matrix structure from a plastic compound. There are of two primary types, namely, open cell and closed cell. Open cell materials rely on the structure of the matrix and elastomeric qualities of the plastic material to provide a dampening effect to impact energies. Closed cell materials augment the inherent structure with air contained in the cells thus storing some of the impact energy by compressing the air. This stored energy in padding systems intended for helmets is generally not preferred because it can cause further trauma to the user. One disadvantage to these materials is their narrow band of responsiveness to the typical range of impact energies. Another disadvantage to these materials is their inability to provide an optimal fit for a wide range of user sizes.
In the current art, one approach to padding is rate sensitive materials, which are very well known. These materials use a range of chemical and/or mechanical means to increase the material's density as the force of impact increases. Under normal conditions these materials are soft, but stiffen when impacted to distribute and absorb impact energy. One disadvantage to these materials is their slow rate of return to normal once compressed which makes them less suitable to multi-impact applications.
Another approach to padding is mechanical materials. These materials combine the inherent energy diffusing qualities of plastic compounds with unique structures such as tubes, domes, channels, etc. One disadvantage to these materials is the narrow band of responsiveness to impact energies. Another disadvantage to these materials is the high degree of stored energy they deliver back through the system after an initial impact.
Another approach to padding is gel materials. These materials generally combine viscous liquids with solid particles and can range from loose to stiff. Like rate sensitive materials, one disadvantage to these materials is their slow rate of return to normal once compressed which makes them less suitable to multi-impact applications. Another disadvantage to these materials is their narrow band or responsiveness to the typical range of impact energies.
Another approach to padding is EPS, mentioned above, often found in bike helmets. These materials are lightweight amalgams of foamed polystyrene beads, which are typically molded into rigid or semi-rigid structures. Impact energy is diffused when the structure dis-integrates upon impact. One disadvantage to these materials is their reliance on dis-integration, which makes them unsuitable to multi-impact applications. Another disadvantage to these materials is the difficulty in knowing if they have been compromised or damaged.
Another approach to padding is expanded polypropylene (EPP). These materials are lightweight amalgams of foamed poly propylene beads, which are typically molded into semi-rigid structures. Impact energy is diffused similarly to a closed cell foam material. One disadvantage to these materials is their inherent capacity to store impact energy and return it to the user's head as a rebound impact.
Yet another approach to padding is the use of air. Two approaches are currently in use in the prior art. First is air contained within a closed system, either in static bags or coupled bags that allow for the air to be transferred from bag to bag. The other uses an orifice to control the rate air is expelled. One disadvantage to these systems is their slow rate of return to normal once compressed which makes them less suitable to multi impact applications.
Performance standards have been developed for some helmet types and other body protective equipment. Bicycle helmets, for example, are subject to US CSPC testing standards. Football helmets are subject to NOCSAE testing standards. Hockey helmets are subject to ASTM testing standards. These test standards have helped to ensure that the protective equipment meets minimum requirements for performance under specified input criteria and testing criteria regardless of brand or cost. While virtually all helmets commercially available pass their respective tests, user injuries with different mechanisms of injury persist across the board. Within the sports category, this may be due in part to participants' average size and weight increasing coupled with a drive to push themselves harder to be more competitive. Recent news coverage of the increase in concussive injuries in American football has raised the question whether current test standards are appropriate for that particular injury. Medical science is discovering new links between brain injuries and trauma mechanisms that are helping to inform better protection, and eventually improved testing standards.
Regardless of application, users are demanding lighter and lower profile helmets with more and more energy attenuation. Added weight creates fatigue in the user, but is also known to increase inertia to the head in collisions. Helmet wearers generally and young sport enthusiasts in particular resist high profile solutions for aesthetic reasons.
In view of the foregoing, there is a demand for a new and novel impact energy attenuation material.
There is a demand for an impact energy attenuation material that is more responsive than prior art materials.
There is a further demand for a new and novel system that can provide impact energy attenuation.
There is a further demand for a system that can provide a custom fit of such a system for optimal performance thereof.